Apparatus for adjusting damped oscillation characteristics in electronic musical instruments



NOV' 19, 1968 MASAMI YAMAZAKI 3,411,393

APPARATUS FOR ADJUSTING DAMPED OSCILLATION CHARACTERISTICS IN ELECTRONIC MUSICAL INSTRUMENTS Filed July 6, 1965 4 Sheets-Sheet 1 INV ENT OR //l/e/WJ/v ATTORNEY 5 om A.:

a T L Masami Yamazaki APPARATUS FOR DAMPED OSCILLATION CHARAC Cs IN ELECTRONIC M C INSTRUMENTS Filed July 6, 1965 4 Sheets-Sheet 2 Nov. 19, 1968 MAsAMl YAMAzAKl 3,411,393 ADJUSTING FIG. 3A

FIG 4 FIG 5 Q comm PRESSURE DISPLACEMENT AMouNT g o 2 s 4 5W o 2 s 4 5mm) o 0 #1 4 4 p 1- 3 8 l2 E i2 g D mvENroR Masami yamaza Rf ATTORNEYS Nov. 19, 1968 MASAMI YAMAZAK-l Filed July 6, 1965 LEVEL LEVEL LEVEL fo 2f sf 4f 5f f FIG. 6A.

1 2f a; 4f 5f f F IG.6C.

4 Sheets-Sheet 3 fo 2f 5f 4f 5f f FIG.6F.

INVENTOR Masami yamazdk ATTORNEYS Nov. 19, 1968 MAsAMl YAMAZAKI 3,411,393

APPARATUS FOR DJUSTING DAMPED OSCILLATION CHARACTERISTICS IN ELECTRONIC MUSICAL INSTRUMENTS Filed July 6, 1965 4 Sheets-Sheel 4 \\\\\\\\\\\A\,\\\\\ -w\\\\\\\\\\\\\\S\\\\\\\\ N ia n #di INV ENT OR Masami ya ma?. aki' Mm//zlwa ATTORNEYS United States Patent O 3,411,393 APPARATUS FOR ADJUSTING DAMPED OSCIL- LATION CHARACTERISTICS IN ELECTRONIC MUSICAL INSTRUMENTS Masami Yamazaki, Yokohama, Japan, assignor to Victor Company of Japan, Limited, Yokohama, Japan, a corporation of Japan Filed July 6, 1965, Ser. No. 469,430 Claims priority, application Japan, July 9, 1964, 39/38,176, 39/38,177, 39/38,178 2 Claims. (Cl. 84-216) ABSTRACT OF THE DISCLOSURE An apparatus for adjusting `damped oscillation characteristics in electronic musical instruments wherein a contact portion Aof the damper, which contacts the oscillating body under pressure is formed with a knife-edge shape and the tone color and damped time of the oscillation is made adjustable by changing the position of the contact portion and the contact pressure.

This invention relates to an apparatus for adjustment of the damped oscillation characteristics in an electronic instrument, especially, to adjust the damped time and damped oscillation characteristics of the voscillating body in an electronic piano.

In an ordinary piano, there is provided a construction such as when a keyboard is pushed, a damper is separated from a string, and when the keyboard returns, the damper contacts with the string and hastens the damped oscillation of the string. But in the conventional electronic piano, there is no construction of damper as in said ordinary piano in order to simplify the construction in the conventional electronic piano, therefore, the damped time of the oscillating body becomes very long and the sound of the electronic piano differs from the sound of the ordinary piano. These are defects.

In accordance with this invention, said defects are obviated by providing a damper wh-ich is always in contact with the string.

A principal object of this invention is to present a novel and useful apparatus for adjusting the damped oscillation characteristics so that the sound of the electronic piano can approach the sound of the ordinary piano.

Another object of this invention is to present an apparatus for adjusting the damped oscillation characteristics -capable of adjusting the damped time and damped oscillation characteristics of the oscillating body in the electronic instrument such as electronic piano.

Further object of this invention is to present an apparatus for adjusting the damped oscillation characteristics capable of changing the tone color of the electronic instrument.

Other objects and advantages of the invention will be evident from the following specification, reference being had to the drawings, in which:

FIG. l is a side view of an oscillating device having a string as an oscillating body and an apparatus for adjusting the damped oscillation characteristics;

FIG. 2 is a plan view thereof;

FIG. 3-A is an enlarged sectional view taken along line III-III of FIG. 2;

FIG. 3-B is an enlarged view of a portion indicated by Zin FIG. 3-A;

FIG. 4 is a graph illustrating the relation a contact pressure between a damper and la string with the damped time of an oscillation;

FIG. 5 is a graph illustrating the relation between F ICC a displacement of the damper and the damped time of the oscillation;

FIGS. 6-A to -F are graphs illustrating a damped state of frequency components of the oscillated string rat various positions of the damper;

FIG. 7 is a side view of an embodiment of this invention in case of fixed position of the damper; and

FIG. 8 is a side View of another embodiment of this invention using an oscillating plate as an oscillating body.

Referring to drawings, FIG. 1 is a side View of an oscillating device having an apparatus for adjusting the damped oscillation characteristics, in which a pin 11 for fixing a string and a pin 12 for adjusting the tension of the string are fixed fon both ends of a frame 10, said string 13 being extended between said pins and beaten by a hammer 14. Further, a damper 16 made of iiexible materials such as, felt, cotton or foaming resin is xed so as to contact with said string 13 on the frame 10 by a bolt 18 and a butterfly nut 19 via a spring 17, and the contact pressure between the damper 16 and string 13 can be changed by adjusting the rotation of said butterily nut 19.

Thus, the damped time of the oscillation of the string 13 can be changed. There is a special relation between the shape of the damper 16 and the damped oscillation characteristics of the string. The higher harmonic component of the wave-lengths which are shorter than the wave-length corresponding to the length of the portion of the string 13 contacting the damper 16 are damped remarkably by said damper 16, and the tone color becomes simple. Then, it is desirable that the contact between the damper 16 and the string 13, be as short as possible. In this invention, the contact part of the damper 16 is formed to a knife edge shape. As a result, the attenuations for the higher harmonics of higher order in the oscillating components of the string 13 are small. Further, as the elements having la special effect for the d-amped oscillation characteristics of the string 13, there is the contact pressure between said string 13 and damper 16, and the distance x between the damper 16 and a supporting point 15 of the string 13. A slot 20 is provided in the frame 10 from the end part of the string to the central part of it so that the fixed position of said damper 16 can be adjusted. The oscillation of the string 13 and its damped speed are controlled and changed by the contact pressure between the string 13 -and damper 16, and said contact pressure can be changedv by the rotation of said buttery nut 19 from a degree such that the contact pressure is not applied in the stationary state of the string 13 to a degree such that the contact pressure is Ialways applied perfectly, so that the damped time of the oscillation can be changed in a wide range accordingly the damped time of the oscillation can be made a desired value. FIG. 3-A shows a state that the string 13 is pressed on the damper 16, and a displacement amount of the ydamper 16 given by the string 13 is shown by y in FIG. 3-B. It is ascertained that the damped oscillation time of the string 13 is in inverse proportion to the contact pressure between the damper 16 and string 13 as a graph shown in FIG. 4. Further, it can be understood that the damped time of said oscillation decreases `according to the increase of said displacement amount y as shown in FIG. 5.

The testing values as shown in FIGS. 4 and 5 were ar- {jivled at experimentally under the conditions as described e ow.

The string (spiral string) is 2.3 mm. in diameter, 20 kg. in tension, 900 mm. in length and the damped time shows a time internal from the maximum level till the level decreased to 20 db. A foaming resin having a knife edge shape is used as a damped material.

As this result, the damped time can be made the same as the damped time of the oscillation in the ordinary piano by adjusting the contact pressure between the damper 16 and string 13 as an oscillating body.

Further, to produce the tone color like the ordinary piano, the basic wave and higher harmonics of the oscillation damped as described above must be damped uniformly and the position of the damper 16 must be defined suc'h that each harmonic component which is Igenerated by beating the string is damped equally since the damped state of the basic wave and higher harmonics is changed according to the position of said damper 16 contact with the string 13.

Now, in FIG. l, the distance, between the supporting point 15 of the string and the position of the damper 16 contact with the string, is made as x and the distance x is cihanged, and the oscillation of the string 13 immediately after beating the string is detected electrically. As the result of the analysis of said oscillation, it can be recognized that higher harmonic components are included in the oscillation as shown in FIG. 6A and the relative Iamplitude of each component has no relation with the distance x between the supporting point 15 and damper 16. In FIG. 6A, the axis of abscissa shows a frequency, and fo shows a fundamental frequency, and 2f, 3f, 4f, 5f and 6] show the secondary higher harmonics, the third higher harmonics and so on respectively. The ordinate shows a level of their oscillating components by db such that the highest level in the basic wave and higher harmonics is db.

According to the same indicating system, after four minutes from when the string is beaten, namely, when the highest level in the oscillating components damps about 20 db compared with the highest level irnmediately after the string is beaten, the oscillation of the string 13 is detected and analyzed similarly, and as the result it can be recognized that the damped oscillation characteristics of the oscillating components is changed according to the position of said damper 16. Namely, if the distance x between the supporting point 15 of said string 13 and the damper 16 is 1%;0 of the total length of the string 13, higher harmonics in higher order damp remarkably as shown in FIG. 6-B and it is not equal to the ordinary piano, so the tone color is different from the piano.

Next, when the position of the damper is shifted and the distance x between the supporting point 15 and damper 16 is changed to about 1A() of the total length of the string 13, the damping of the higher harmonics becomes large in some degree in comparison with the state of the oscillating components immediately after the string is beaten as shown in FIG. 6-C. Similarly, when the damper 16 is positioned at M26 of the total length of the string, the relative amplitude between the fundamental wave and higher harmonics are almost constant with that of the oscillating components immediately after the string is beaten as shown in FIG. 6-D, and lwhich shows that almost all the oscillating components are damped equally. Further, 'when the damper is positioned at J/10 of the total length of the string, the damping of the fundamental wave is recognized in some degree as shown in FIG. 6-E. But when the damper is positioned at 1/s of the total length of the string, the fundamental wave is damped remarkably as shown in FIG. 6-F, so the tone color is heard as if the tone scale becomes high and is felt as different from the tone color of the ordinary piano.

According to the results of the analysis of said oscillating wave and of audition, if the position contacting the damper 16 with the string 13, that is, the distance x between the supporting point 15 and damper 16 is selected in the range of 1/40-1/10 of the total length of the string 13, it can be understood that the tone color does not change by the progress of time after the string is beaten, even if the damper 16 always contacts the String 13. Moreover it can be understood that the damped time of the oscillation changes when the contact pressure between the damper 16 and string 13 is changed, but the tone color does not change.

As described above, in the electronic instrument having an oscillating body for making a sound, the tone color and damped time of the oscillation can be adjusted and a sound similar to a desired instrument can be formed by combining three elements which are the shape of the damper contacting said oscillating body, the contact pressure between said damper and oscillating body for a making a sound and the contact position of the damper to the total length of said oscillating body.

In FIG. 7, there is shown another embodiment of this invention, in which a pin 32 for adjusting the tension of a string 31 and a pin 33 for fixing the string 31 are provided on a frame 30, and an oscillation damping device 34 is positioned on the frame 30 so as to contact said string 311, said position being determined such that the distance between the oscillation damping device 34 and the supporting point 35 is in the range of 1an-JA@ of the total len-gth of the string and the tone color becomes more similar to the tone color of the ordinary piano, and a hammer 316 is provided suo'h that said string is beaten by it. FIG. 8 shows other embodiment of this invention, in Iwhich an apparatus 41 for adjustment of the damped oscillation characteristics is iixed to a frame 42 in case of using an oscillating plate 40 as an oscillating body in an electric instrument and a hammer 43 is provided so as to beat said oscillating plate 40, said oscillating plate 40 being fixed on the frame 42 via a fixed part 44.

In this case, the damped oscillation characteristics can be adjusted similarly as described above.

What I claim is:

1. An apparatus for adjusting `damped oscillation characteristics in an electronic musical instrument comprising an oscillating body for making la sound, a damper provided wvith a knife edge portion, means for contacting said knife edge portion of the damper with said oscillating body, means for adjusting contact pressure between said knife edge portion and said oscillating body, and means for adjusting the position of contact between said knife edge portion and said oscillating body along said ocillating body, the damped oscillation time and tone color being changed according to said contact pressure and said contact position respectively.

2. An apparatus for adjusting damped oscillation characteristics in an electronic piano comprising an oscillating body for making a sound, a damper provided with a knife edge portion, means for contacting said knife edge portion of the damper with said oscillating body, means for adjustably setting the distance between said knife edge portion and a supporting point of said oscillating body in a range of 1/0-1/10 of the total length of said oscillating body, and means for adjusting contact pressure between said knife edge portion and said oscillating body, the damped oscillating time of said oscillating body being controlled by changing said contact pressure.

References Cited UNITED STATES PATENTS 5/1961 Sabine 84--216 7/1956 Brown 84-2l7 

